Environmental Factors Related to Gastric Cancer Associated with Epstein-Barr Virus in Colombia

Epstein-Barr virus (EBV)-encoded small RNA can be detected in about 1-17 % of gastric carcinomas. To elucidatelifestyles and other factors related to such an EBV-associated gastric carcinoma (EBV-GC), we conducted a casecontrolstudy in Cali, Colombia. The study subjects were 368 patients with gastric carcinoma newly diagnosed duringthe period between September 2000 and June 2003, including 42 EBV-GC cases. We obtained information on lifestyles,dietary habits, and occupational exposure by a questionnaire. The frequency of EBV-GC was related to birth orderof patients (P for trend =0.025). More precisely, EBV-GC was much less frequent among the patients who were theeldest child in a family (P=0.007). Those findings were contrary to what was reported by the study conducted inJapan, where EBV-GC was more frequently observed among eldest brothers/sisters. A possible explanation for theapparently conflicting results is that EBV-GC risk is related to the age at first EBV infection but its relationship isnot monotonic. In addition to the relationship with birth order, the present study showed that high salt intake andmetal dust exposure may be related to EBV-GC as reported by the Japanese study although these associationsobserved in the present study were not statistically significant. No significant association was observed in otherfactors, including dietary habits. Further studies seem warranted to elucidate the difference between Japan andColombia with respect to the environmental factors related to EBV-GC cases.